Title: Nonlinear Frame Element with Shear–Flexure Interaction for Seismic Analysis of Non-Ductile Reinforced Concrete Columns
Author(s): Worathep Sae-Long, Suchart Limkatanyu , Woraphot Prachasaree, Suksun Horpibulsuk and Pattamed panedpojaman
Appears on pages(s):
Keywords: seismic nonlinear analysis, reinforced concrete, ﬁber frame element, shear–ﬂexure interaction, shear failure
This paper presents and emphasizes the essence of inclusion of shear response and shear–ﬂexural interaction in the investigation of reinforced concrete (RC) columns characterized by light and inadequately (substandard) detailed transverse reinforcement. This column type commonly exists in old-constructed RC frame buildings before the regulation of modern seismic codes. A stiﬀness-based RC frame element with shear–ﬂexure interaction is formulated within the framework of Timoshenko beam kinematics assumption. Linked displacement interpolation functions are employed to remedy the problematic shear-locking phenomenon. The axial and ﬂexural actions are interacted via the ﬁber-section model while shear-strength deterioration with inelastic ﬂexural deformations is accounted for within the framework of the UCSD shear-strength model. The numerical procedure for shear–ﬂexure interaction is modiﬁed from the Mergos–Kappos procedure. The proposed element is simple, computationally eﬃcient and able to describe several salient features of RC columns with substandard detailed transverse reinforcement, including gradual spread inelasticity, shear–ﬂexure coupling eﬀects, and shear-strength deterioration with increasing curvature ductility. Three correlation studies are conducted to examine the model accuracy and its capability to predict the rather complex responses of non-ductile RC columns. Comparison with conventional ﬂexural frame element is also presented to emphasize the essence of inclusion of shear response and shear–ﬂexure interaction.